May 1995, Volume 45, Issue 5

Original Article

Apical Hypertrophic Cardiomyopathy in Pakistan: Electrocardiographic, Echocardiographic and Myocardial Scintigraphic Features

Shehbaz A. Kureshi  ( Department of Cardiology, Federal Government Services Hospital, Islamabad. )
Shaukat M. Malik  ( Department of Cardiology, Pakistan Institute of Medical Sciences, Islamabad. )
Waqar Hyder  ( Department of Nuclear Medicine, Oncology and Radiotherapy Institute, Islamabad. )

Abstract

Apical hypertrophic cardiomyopathy is a recently recognised entity, with typical electrocardiographic, echocardiographic and myocardial scintigraphic features. Thallium imaging is more sensitive than echocardiography, but electrocardiogram appears to be an important clue to its diagnosis which shows changes in the mid precordial leads in most of the patients (JPMA 45:117,1995).

Introduction

Hypertrophic cardiomyopathy (HC) is a subset of cardiomyopathies, whose morphologic features have been described in many reports1,2 and in HCfurthersubgroups have been recognised depending upon the site of hypertrophy, which may have diagnostic and prognostic implications3,4. Apical hypertrophy of the left ventricle has been proposed in Japanese literature5 and there are isolated case reports from South Africa, Asia and America. Apical hypertrophic cardiomyopathy was first reported in a group of Pakistani patients in 19856 and its clinical and angiographic features have been described. Different non-invasive and invasive diagnostic modalities are used to evaluate myocardial hyper­trophy: echocardiography, my ocardial scintigraphy, gated cardiac blood pool scanning, X-ray computed tomography and contrast left ventriculography. Echocardiography is the most widely used method, but often it is inadequate or technically poorinquality, inpatientswithchromc obstructive lung disease, obesity and other conditions. Also apex and lowerventricular septum are difficult to evaluate echocardiog­raphically evenby 2- D sector scanning. Myocardial scintigra­phy with thallium-201 has the advantage of visualising the entire LV myocardium in all patients. This paper describes three Pakistani patients with apical hypertrophic cardiomyopathy with distinctive electrocardiograms and echocardiographic features diagnosed by conventional thal­lium-201 planar imaging.

Case 1
A 45-years old male was admitted to the CCU with a history of atypical chest pain and fainting triggered during strenuous activity and abnormal findings on electrocardio­gram. The patient was in excellent health until the day of admission. Serial cardiac enzymes were not elevated and electrocardiogram did not change. The only risk factor was obesity. There is a strong family history of diabetes mellitus and ischaemic heart disease. On physical examination there was mild hypertension and an audible S4. Inderal 40mg three times daily and Moduretic one tablet daily were prescribed. Electrocardiogram showed abnormal changes (tall R waves and giant negative T waves) in mid precordial leads. R wave was highest (42 mm) in V4 and T wave was deepest in V4 (16 mm). QRS axis was normal and the highest R wave was noted in limb lead II. ST was depressed 2 mm in V2, V3 and V4 and septal q was absent (Figure 1).

Graded exercise test was performed on a bicycle ergometer with 25-W increments every 3 minutes. Patient was able to exercise for 14 minutes and the test was terminated due to fatigue. After 12 minutes of exercise patient felt slight pinching in the chest. There were no ST or T wave changes seen at peak exercise, or during the recovery period. The morning dose of Inderal on the day of exercise was omitted. 2-D echocardiogram showed lower septal and lower free wall hypertrophy and narrowing of LV cavity towards the apex (Figure 2).

A diagnosis of apical hypertrophic cardiornyopathy was made on these findings as previously described5. Resting thallium images were obtained in anterior, left’unterior oblique 450 and left anterior oblique 700 projections after intravenous injection of 2 Mci of thallium-201. Inthe thalliumimages markedthickeningofthe apex was clearly visualised. No perfusion defects or areas of relative hypoperfusion were seen (Figure3).


Case 2
A 55 year old male presented to the Casualty with a histoiy of discomfort in left shoulder non-radiating in nature and not associated with sweating. The only cardiac finding was a short grade 1/6 systolic ejection murmur at the left sternal border. Electrocardiogram showed normal QRS axis with limb lead II showing highest R wave. Tall R waves and giant negative T waves were seen in midprecordial leads. R wave was tallest in V4 (56 mm) and T wave was deepest in V4 (24mm). Twaves were also inverted in limb leads, inaVL and aVF. Graded exercise was not performed in this case. Patient was evaluated echocardiographically using 2-D sector scan­ner in the left recumbent position. Lower septal hypertrophy, lower free wall hypertrophy and significant narrowing of the apical LV cavity was seen. Resting thallium images were obtained as in the previous case. Marked thickening of the apex was clearly seen and none of the images showed any perfusion defect or areas of relative hypoperfusion.
Case 3
A 48 year old male developed palpitation when he was given intravenous fluids afterhaving had diarrheafora couple of days. He later presented to the Cardiology department with sweating, palpitation and breathlessness on exertion. Exanii­nation of the cardiovascular system revealed a short 2/6 systolic murmur at the left sternal border. As in the previous two cases tall R waves and giant negative T waves were seen in the midprecordial leads, marked thickening of the apex. Echocardiographic features were consistent with apical hy­pertrophic cardiomyopathy (Figure 4).

Thallium images showed marked thickening of the apex.

Discussion

Yamaguchi et al5 reported giant negative T waves in a series of hypertrophic cardiomyopathy which they labelled as “apical hypertrophy”. The electrocardiographic pattern satis­fying the diagnostic criteria of L\\\\’H with the most remarkable changes in the midprecordial leads, Lead II, with a normal axis, is characteristic for non-obstructive hypertrophic cardiomyopathy7. Thallium-201 single-photon emission-computed tomography (SPECT) with a rotating gamma camera can provide useful clinical information about regional myocardial hypertrophy8. Kuzeshi et a19 showed that in APH the m.idprecordial leads reflected abnormal changes which were most significant in lead V4 and the that the morphologic fmdings in APH derived by SPECT coincided with the ECG findings. In our patients the T wave was most deeply inverted in lead V4 where the R wave was also the highest. The giant negative T waves might be secondary to the result of reversed order of repolarisation from the hypertrophic lower septum and apical area7. Although relative myocardial ischaemia may be another factor related to T wave change, true coronary artery disease is not the cause. The electrocardiographic abnormalities in patients with apical hypertrophy may serve as sensitive diagnostic markers forthe disease. The cases inthe report of Maronet al10 showed features different from the Japanese patients, probably be­cause only the septum rather than the entire apical segment is involved. Our patients demonstrated the typical ECG changes characteristic of APH as described in earlier reports. In all three patients 2-D sector scan showed lower septal hypertro­phy, lower free wall hypertrophy and towards the apex the LV cavity was significantly narrowed. Echocardiographic tech­niques may not always adequately visualise this type of distal hypertrophy. A recent study8 in Japanese patients with APH demonstmted adequate visualisation of apical hypertrophy by 2-D echocardiography in only 6 of 10 patients. Therefore, 2-D sector scanning may not be an adequate scanning method for all types of hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy has been evaluated by conventional thallium-20 1 myocardial imaging by Bulkely et al11. who found a thickened apex in both obstructive and non-obstructive types of HC. Suzuki et al8 showed that a thickened apex was characteristic of non-obstnictive HC with giant negative T waves but not of obstructive HC orconcentnc LV hypertrophy. This apparent discrepancy between conven­tional scintigraphy and SPECT imaging may be related to the radionuclide superimposition of conventional thallium-201 myocardial imaging. In our cases apical hypertrophy was clearly seen by the conventional thallium imaging, but the number of cases is small to make any inference (Table).

Most patients with apical HC are asymptomatic and over 90% are male and usually over 40 years5. The most common symptom appears to be chest pain (anginal or
atypical), followed by dyspnea on exertion, palpitations, dizziness and easy fatigue5 . These patients do not show appreciable impairment of left ventricular function or symp­toms of heart failure. Stress test in our patients had shown a good exercise tolerance without any ST segment changes. Abnormal cardiac performance during exercise could be an important factor of sudden death. Koga et al12 have shown that risk of sudden death was significantly higher in patients with positive single Master’s two-step test. Graded exercise test appears a good way to assess prognosis in patients with apical hypertrophic cardiomyopathy. Familial occurrence is uncom­mon in APH and hypertension and strenuous physical activity are probably associated risk factors. APH appears to have an excellent prognosis in contrast to other form of hypertrophic cardiomyopathy12. Few symptoms may be the cause of lack of case reports or the distinctive electrocardiogram is not recognised and so the diagnosis is not considered. Possibly in our patients the electrocardiographic changes evolved over a passage of time. Patients with striking electrocardiographic T wave changes may represent the final product of a hypertrophic process changing in response to unknown stimuli such as humomi factors, as suggested by Yamaguchi and colleagues5. As our patients did not show any evidence of perfusion defects or areas of relative hypoperfusion on thallium-201 myocardial imaging and had typical diagnostic features of APH, coronary angiogmphy was not performed.

References

1. Braunwald, E., Morrow, A. G., Cornell, W. P. et at. Idiopathic hypertrophic subaortic stenosis: Clinical hemodynamic and angiographic manifestations. Am. J. Med., 1960;29:924-45.
2. Roberts, W. C. and Ferrans, V. J. Pathological aspects of certain cardiomyopa­thies. Circ. Res., 1974;34,35(Suppl. ll):11-128,11-144.
3. Steingo, L., Dansky, R., Pocock, W. A. et al. Apical hypertrophic non-obstruc­tive cardiomyopathy. Am. Heart J., 1982,104;635-37.
4. Mckenna, W., Deanfield, J., Faruqui, A. et al. Prognosis in hypertrophic cardiomyopathy: Role of age and clinical, electrocardiographic and haemody­namic feature. Am. J. Cardiol., 1981 ;47:532-38.
5. Yamaguchi, H., Ishimura, T., Nishiyama, S. etal. Hypertrophic non-obstructive cardiomyopathy with giant negative T waves (apical hypertrophy): ventricu­lographic and echocardiographic features in 30 patients. Am. J. Cardiol., 1979;44;401-12.
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8. Suzuki, Y., Kodota, K., Nohara, R. et al. Recognition of regional hypertrophy in hypertrophic cardiomyopathy using thallium-201 emission computed tomogra­phy: comparison with two-dimensional echocardiography. Am. 3. Cardiol., 1984;53:1095-1102.
9. Kureshi, S. A.,Kambara,H., Suzuki, Y. et al. Electrocardiographic evaluation of apical hypertrophic cardiomyopathy: A co-relation with thallium-201 imagmg with single photon emission computed tomography. Sydney, Australia, XV World Congress on Diseases of the Chest, 1985.
10. Maron, B. 3., Bonow, R. 0., Seshagiri, T N. R. et al. Hypertrophic cardiomyopathy with ventricular septal hypertrophy localized to apical region of the left ventricle (Apical hypertrophic cardiomyopathy). Am. J. Cardiol., 1982;49: 1838-48.
11. Bulkely, B. H., Rouleau, J., Strauss, H. W. et al. Idiopathic hypertrophic subaortic stenosis detection by thallium-201 1 myocardial perfusion imaging. N. Eng. J. Med., 1975;293;1113-16.
12. Koga, y., Itaya, K. and Toshima, H. Prognosis in hypertrophic cardiomyopathy. Am. Heart 3., 1984;108:351-59.

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